Multi-segmentation of JOS-3 thermoregulation model: Validation under steady-state and transient conditions

Proper thermoregulation in humans plays a vital role in maintaining physiological homeostasis and is crucial for survival. Accurate prediction of the human thermal response through thermoregulation models has many potential benefits in the design and optimization of temperature management strategies and thus, human well-being. This paper aims to update the multi-node JOS-3 thermoregulation model by a multi-segmentation of the 18 original body parts. The original model was further segmented according to body thermal sensitivity maps to potentially improve its accuracy in assessing the body's thermal response due to transient, non-uniform thermal environments such as the ones created by personalized environmental comfort systems (PECS). The modified model was validated with two existing experimental data sets conducted in climatic chambers. The first set of experimental data was obtained at steady-state temperatures in cool (20 °C), neutral (25 °C) and warm (30 °C) environments. The second experimental data set consisted of measurements under consecutive transients of temperature (i.e., 23 °C to 17 °C and 26 °C to 13 °C), clothing insulation (0.65 clo to 1.03 clo and vice versa) and activity level (resting to walking). Overall, results showed that the modified model improved the prediction accuracy of segmental and mean skin temperatures under steady-state conditions by 15 % to 68 % as well as under transient conditions by 26 % to 61 %. The improvement was notable for upper body segments. It also kept a stable prediction range under a wide range of thermal conditions (13 °C and 30 °C). The improvement was statistically significant with medium to large effect size. The modified model exhibited a better transient response making it suitable for PECS performance evaluation.